The Arizona sentinel., 1887-05-14

EuecUS-Lu0dr SeaSs
 Full of interest is the lesson taught by the moon. For there on her surface remain, still extant, still retaining their ring form, such craters as have not existed on the earth during mill ions of past years.
 The interest of our lunar lessons about the earth's past eliminates, to my mind, when we consider the signifi- canoe of those few ranges of mount aims which exist on the moon. We see at once that we can not explain this feature, as we can explain the com parative smallness of the terrestrial craters as due to the disappearance of elevations formerly existing. If the moon had ever had mountain ranges corresponding with the HimalaYas and the Andes on the earth, such ranges would still exist upon her airless and waterless surface. Ranges as impo tant as either of these may have existed on the earth in past ages and since dis appeared. Indeed we know that the very size of the Himalayas and Andes attest their comparative youth. The Dofrefields, in Scandinavia, are much less elevated, because they are much older and have experienced much more wear and tear, ana still older mountain ranges which may formerly have lowered to even greater heights have doubtless long since yielded to the denuding forces which re- side in air and water worked by the mighty hand of terrestrial gravity. But we know that on the moon the denuding forces were so much weaker and acted during so much shorter a time that assuredly it would not be because of their action that fewer and less lofty mountain ranges would ex- ist on the moon than on the earth.
 The answer to what at first seems enigmatical is seen to be altogether simple so soon as we consider what mountain ranges are. So long as ge- ologists regarded them as mere prod ucts of upheaval one could recognize no reason why the mountain ranges on the moon should not be relatively as numerous and important as those on the earth. But geologists no longer regard them thus. They know that the masses out of which our mountain ranges have been carved and chiseled by deruding forces were themselves r,roduo+S oF donuJo+ o+iop Tpctood of being upheaved, our mountain ranges were deposited; instead of indicating steady uprising, they speak of the steady down-sinking of the crust where their crests now appear. In the case of the Alps. the Himalayas, the Rocky mountains, and other such ranges as comparative youth (so that enough of their structure still remains to speak of their past history), we find that layer after layer of mat ter, the product, be it remembered, of denudation, was deposited beneath the surface of the sea, along gradually sinking trough-like depressions, until a thickness of more than ten miles was in many places attained. Then. in deed, process of uprising began. Yet even that resulted from a much more important process of down-sinking or contraction. Immense areas contracting all around the long troughfull of de- posted matter, this matter was gradu- ally forced up-shouldered up, as it were, like an immense seam in the crust of the earth. We still find evi- dence of the tremendous energy of the forces which then acted on the deep layers of deposited matter; for these, despite their vast mass, despite their Uen-mile thickness, were twisted and tortured and heaved so irresistibly (though slowly that the heat de- veloped in the process metamorphosed the material of the rocks until in many regions all trace of the sedimentary character they originally had disap- peared. In many cases layers of inn mense thickness once horizontal were turned up vertically; in some cases such layers were absolutely inverted.
 Then came the work of yet other myriads of years q use the words in their literal sense, meaning tens of thousands of years) of denuding processes, quarrying the mountain peaks out of the surrounding masses of hard yet more yielding material This later denuding work, however, unlike the former, went to reduce the height of the mountain range. Every thou sand years in the earlier stages of de- nundation had added to the mass of material out of which that range was to be formed.
 Can we wonder if on the moon where denuding forces have been so much